Report  |  Sentencing

Factors Influencing the Sentencing of Convicted Felons in Illinois

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The number of individuals under some form of correctional supervision for a felony conviction has more than doubled in Illinois since the mid-1980s; between 2000 and 2017, more than 120,000 per year were in the custody of Illinois’ correctional system, either on probation, in prison, or on parole.[1]

While the number of individuals under correctional supervision has remained steady since 2000 in Illinois, where they fall has shifted. Prior to 1990, more than half of those convicted of felonies were supervised by probation departments throughout the state and less than half were either in prison or on mandatory supervised release (i.e., MSR or “parole”). Since then, the distribution has shifted and approximately 60 percent of that population are either in prison or have recently been released onto MSR, while roughly 40 percent remain under probation supervision.

This shift is partially due to a change in the use of prison in Illinois. Between 1985 and 2009 the proportion of convicted felons sentenced to prison increased from 42 to 50 percent.[2] During this same period, Illinois saw a 100-percent jump in the number of individuals charged with a felony processed through Illinois courts. The combination of increased felony cases and the increased likelihood of receiving a prison sentence following a felony conviction caused significant growth in the number of individuals in custody of the Illinois Department of Correction both in prison and under MSR (parole).

However, the use of prison sanctions varies by county. When the proportion of individuals sentenced to prison is examined across each of Illinois’ 102 counties, a substantial variation in the rate of prison utilization is seen. DuPage County, for example, consistently has sent a smaller proportion of individuals convicted of a felony to prison relative to the state average, while Cook County consistently has sent a larger proportion to prison. As Winnebago County and Madison County experienced a steady decrease in the proportion of individuals sentenced to prison, Sangamon County experienced a slight increase. The differences are dramatic; by 2015, fewer than 20 percent of individuals convicted of a felony were sentenced to prison in some counties, while in other counties more than 60 percent received a prison sentence.

Current Study

While research performed in jurisdictions across the country has long held that individual and case characteristics, such as age, race, gender, criminal history and current offense, serve as predictors for sentences to prison, less is known about how community-level characteristics influence these sentences. Further, the influence of these factors on prison utilization has not been systematically or objectively examined in Illinois.

The current research, conducted by Loyola University Chicago’s Center for Criminal Justice Research, Policy and Practice and supported by the Illinois Criminal Justice Information Authority, examined not only how individual characteristics influence sentencing, but how the community context and characteristics also may play a role in whether a jurisdiction is more likely use a prison sentence as a sanction. These characteristics can range from the extent and nature of crime in the community, the availability of alternatives to prison or other programs, and the effectiveness of probation in a given jurisdiction.

Because many decisions regarding programming and strategies to reduce prison utilization and improve community safety are made at the county level, it is important to understand what influences sentencing. Researchers examined current existing statewide data to determine the influence of defendant- and case-level characteristics on sentencing outcomes among those convicted of a felony and gauge the degree to which sentencing practices vary across Illinois counties once these defendant- and case-level characteristics are taken into account.

Methodology

Researchers obtained incident-level data from the Illinois State Police Criminal History Record Information System (CHRI) dataset on all arrests occurring between 2012 and 2014 that could potentially result in a prison sentence. These data included detail on every felony arrest and every misdemeanor arrest that could be elevated to a felony-level under specific circumstances. The data sample included 115,442 unique individuals. Arrest charges and convictions were ranked by severity and classified into five distinct offense types: violent, illegal possession of weapons, property, drug law violations, and “other”. Sentencing outcomes were examined across two variables: whether the defendant received a prison sentence following a felony conviction and the length of the prison sentence imposed.

The analyses also took into account defendant characteristics, such as gender, race, and age, as well as the extent and nature of the defendant’s criminal history, including the number of prior arrests, prior felony convictions, and prior prison sentences. In addition, case-level characteristics, such as number of conviction charges and the severity of the most serious conviction charge (offense class) were analyzed.

Time served in pre-trial detention can influence a judge at sentencing. CHRI does not capture time served in pre-trial detention, but a proxy measure was developed to capture whether a convicted defendant received credit for time served in pre-trial detention. Another factor shown in previous research to influence sentencing is whether a guilty plea was entered. Because this information is not captured in CHRI information, a proxy measure was developed to identify a reduction in the number of charges from arrest to conviction or a reduction in the severity of the charges, as they may signal a plea deal.

To examine the effect of county-level characteristics on sentencing, the researchers looked at the crime rate and “clearance rate” (dividing arrests by reported offenses) of jurisdictions as reported to the Illinois State Police through the Illinois Uniform Crime Report for 2012. The felony filing rate, guilty plea rate, and prison utilization rate (percent of felony convictions resulting in a sentence to prison) were derived from the 2012 Annual Report of the Administrative Office of the Illinois Courts. The 2010 U.S. Census provided data on race, median household income, and population density, while election data was used to measure voter turnout (a proxy for civic engagement) and the percentage of residents voting for a Democratic governor. Finally, a variable capturing whether the county has a jail located within its boundaries was included to determine if those counties without a jail would be more likely to utilize prison since they lack a readily available local option to incarcerate following a conviction.

Findings

Just over 48 percent of those convicted of a felony in Illinois during the sampling period were sentenced to prison, with an average sentence length of 3.8 years (Table 1). Nearly 84 percent of individuals convicted of a felony were male, 50 percent were non-white, and 34 percent were under the age of 25. More individuals sentenced to prison during the study period were male, non-white and had numerous prior arrests, prior felony convictions, and prison sentences on their records. For example, of those convicted of a felony, 56 percent had at least one other prior conviction for a felony, but among those sentenced to prison, 74 percent had one or more prior felony convictions. Similarly, 36 percent of those convicted of a felony in the sample had a prior prison sentence, but among those individuals sentenced to prison for their current felony conviction, nearly 56 percent had a prior prison sentence.

Table 1

A total of 43 percent of those sampled were convicted of a Class 4 felony, the least serious felony offense, and 38 percent of those sentenced to prison were sentenced for a Class 4 felony. Most individuals were convicted of a non-violent offense; almost one-third (33 percent) were convicted of a drug law violation and 28 percent were convicted of a property crime. Similarly, of those sentenced to prison, nearly 31 percent were sentenced on a drug law violation and 28 percent were sentenced for a property crime. Just 23 percent were sentenced to prison for a violent or weapon offense.

An examination of county-level characteristics shows that while nearly half (48 percent) of those convicted of a felony during the study period were sentenced to prisons across the state, this percentage varied by county, ranging from 21 percent in one county to over 63 percent in another. Prison sentence lengths also varied by county, ranging from an average of 1 year to over 6 years, with a statewide average of 3.8 years.

Illinois counties are diverse on a number of factors that may contribute to the variation in sentencing and prison utilization. Crime rates based on the number of offenses per 100,000 population ranged from a low of 675 to highs over 10,000. Accordingly, some counties handled relatively small felony filing caseloads at 511 cases per capita, while other counties managed caseloads of over 3,000. Counties also were diverse on measures of demographics, income, voter participation, and the percentage of Democratic voters.

So what characteristics influence the likelihood that a person convicted of a felony will be sentenced to prison? Not considering other factors, such as criminal history and offense type, Table 2 shows a relationship between race and gender. Black defendants convicted of a felony were more likely than white defendants to be sentenced to prison, at 57 percent and 39 percent, respectively. In addition, 52 percent of men convicted of a felony were sentenced to prison compared to 29 percent of women.

Table 2

However, criminal history played the strongest role in whether an individual was sentenced to prison for a felony conviction. For example, 64 percent of those with a prior felony conviction were sentenced to prison, compared to 28 percent of those without a prior felony conviction. Most individuals with past prison sentences in their criminal histories were imprisoned for a felony conviction (75 percent), compared to 33 percent without a prison sentence in their history.

Looking at case-level characteristics, the class of offense also influenced sentencing, as the more serious felony class offenses were more likely to result in a prison sentence. While the strongest predictor of being sentenced to prison was whether the defendant had a previous prison sentence, the second most influential factor was whether the defendant received credit for time served (a proxy measure for pre-trial detention). Those who received credit for time served as part of their sentence were more likely to be sentenced to prison (60 percent) compared to those who did not (31 percent). The proxy measure for plea bargaining (reduction in the number of charges from arrest to conviction) did not show an influence over whether a prison sentence was ordered.

The variables measuring county characteristics that were included in the analyses were not found to be related to whether or not a convicted felon was sentenced to prison. However, even after statistically accounting for the influence of defendant, case, and county characteristics, there was still considerable variation in the use of prison across Illinois’ counties. For example, the odds of being sentenced to prison was 28 percent higher in Cook County than anywhere else in Illinois after controlling for defendant and case characteristics, while in Winnebago County the odds of being sentenced to prison was almost 50 percent lower than the rest of Illinois. However, as described, the considerable variation in prison use across counties did not appear to be explained by factors such as higher crime rates, lower clearance rates, higher case filing rates, county resident population demographics, income, or voting patterns.

Implications

Given that a person’s initial prison sentence plays a strong role in whether or not a future prison sentence will be imposed, there are significant implications in the use of prison as a sentencing option. All things being equal, individuals previously sentenced to prison were much more likely to be sentenced to prison again. This research revealed that those previously sentenced to probation also were more likely to be sentenced to prison. Prior arrests, regardless of prior convictions or sentences to prison, also increased the likelihood of a future prison sentence.

While this research could not pinpoint specific county-level characteristics that contribute to the county variations, these variations still existed even after taking into account defendant and case characteristics.

Data on other factors that may influence sentencing, such as private counsel versus a public defender or cases disposed through trial rather than a guilty plea, are not collected in the CHRI system, and, therefore, were not considered in this study. These information gaps limit the ability to fully understand the factors that influence sentencing. However, given the lack of detailed and publicly available statewide information on sentencing, CHRI data should continue to be analyzed to determine sentencing patterns and how defendant and case characteristics influence the imposition of a prison sentence. Future analyses could support data-driven policy making and inform the degree to which programming interventions influence sentencing practices.

This project was supported by Grant #16-DJ-BX-0083, awarded to the Illinois Criminal Justice Information Authority by the U.S. Department of Justice Office of Justice Programs’ Bureau of Justice Assistance. Points of view or opinions contained within this document are those of the authors and do not necessarily represent the official position or policies of the U.S. Department of Justice. Research was conducted by Dr. David Olson and Dr. Donald Stemen of Loyola University Chicago, Department of Criminal Justice and Criminology and the Center for Criminal Justice Research, Policy and Practice. For more information, please contact Tracy Hahn, Manager of the Center for Sponsored Research and Program Development at ICJIA: Tracy.Hahn@Illinois.gov.



  1. Analyses by Loyola’s Center for Criminal Justice Research, Policy and Practice of published data from the Illinois Administrative Office of the Illinois Courts and the Illinois Department of Corrections. ↩︎

  2. Analyses by Loyola’s Center for Criminal Justice Research, Policy and Practice of published data from the Illinois Administrative Office of the Illinois Courts. ↩︎

Factors Influencing the Sentencing of Convicted Felons in Illinois